Electronic rotation direction finder



Sept. 24, 1946.

H. G. BUSIGNIES ELECTRONIC ROTATION DIRECTION FINDER FiledMarGh 5, 19412 Sheets-Sheet l INVENTOR. /yH//f/ c.' 55s/@M55 ATTOHAJEY sept. 24,1946. H, G, BU'S'IGMES v2,408,039

ELECTRONIC ROTATION DIRECTIN FINDER Filed March 5, 1941 Z-SheetS-Sheel.2

INVENTOR. f/WH/ c: 5v5/@Amas BY ATTOPN Patented Sept. 24, 1946ELECTRONIC ROTATION DIRECTION FINDER Henri G. Busignies, Forest Hills,N. Y., assignor to International Standard Electric Corporation, NewYork, N. Y., a corporation of Delaware Application March 5, 1941, SerialNo. 381,840

3 Claims.

kthe rotating parts.

It is an object of my invention to provide electronic means forproducing the desired rotary eiect of the antenna without the use ofmechanical rotating parts.

Furthermore, in systems wherein rotary goniometers are used with acathode ray indicator it is necessary to provide some means for assuringthat the rotation of the cathode ray is rotated in proper timed relationwith the goniometer rotation.

It is a further object of any invention to provide a means operated intimed relation with the signals producing the effective rotation of theantenna to simultaneously rotate the beam of a cathode ray tube.

The above recited objects may be achieved according to my invention byproviding a phase splitting network and vacuum tube arrangement coupledto a pair of crossed antennas to produce an effective rotation. Theenergy derived from this phase splitter is applied to the deflectingplates of a cathode ray indicator, with frequency multiplication ifdesired, to produce the desired timed rotation of the cathode beam. Theresultant signal from thel loops is applied to the cathode ray tube toproduce signal indications, preferably by achieving radial deectionthrough velocity modulation. Alternatively the signal may be applied toa signal grid in the cathode ray tube and lateral deiiections may beproduced in proper timed relation by a relaxation oscillator.

In accordance with the above features of my invention it is a furtherobject of my invention to provide a cathode ray indicator in which adirective signal is produced on the screen by an arrangement includingmeans for laterally deflecting the beam by velocity modulation.

When the beam is caused to deflect radially from any position, eitherthe center or outward, by received signals, it is desirable that thebeam be suppressed during the times that the signal indications are notelective. Accordingly, it is a further object of my invention to providemeans' 2 controlled by signal voltages for rendering the beam etectiveor ineffective.

A better understanding of my invention and the objects and featuresthereof may be had from the particular description of some modificationsof my invention made with reference to the accompanying drawings, inwhich Fig. 1 shows a general schematic view of a direction iinderaccording to my invention;

Figs. 2 and 3 show alternate grid control means for the indicator tube;

Fig. 4 shows an alternative indicator arrangement, and

Figs. 5 and 6 show cathode ray screens used to explain the operation ofthe circuit of Fig. 4.

In Fig, 1 is shown an antenna system comprising a pair of dipoles l, Iand a second pair of dipoles 2, 2 connected together to act as crosseddirectional receiving units. To antenna l is coupled a circuit 3, theopposite sides of which are applied to push-pull related grids in a tube4, and with antenna system 2 is coupled a circuit 5 coupledin push-pullrelation to grids of a tube 6. The anodes of both the double tubes 4 and6 are connected in parallel to a common feed line l. An alternatingcurrent source I0 is provided connected over a transformer I I to anadjustable phase splitting circuit I2, the separate phases of which arecoupled if desired through amplifiers I3, lll, to individual circuitsI5, I6. Circuit I5 is coup-led to the grids of tube 4, the couplingcircuit being grounded at its mid-point so vthat energy at o phasedierence is applied to the grids of tube 4. Circuit I6 in which theenergy is in phase quadrature to that of circuit I5, is similarlycoupled to the grids of tube i5. It should be understood that instead ofthe combined tubes i and 6 shown, separate vacuum tubes could be used inthis arrangement.

It will be noted that energy is supplied to the grids of tubes 4 and 6from the circuits l5, IB in such a manner that the output energy in line'l will be of a wave formation exactly the same as if a rotatablegoniometer were provided. Accordingly, by the use of this arrangement aneffective rotation of the directional antennas is achieved without thenecessity of providing mechanically rotating parts.

In order to obtain a directional indication, a cathode ray tube 20 isprovided. The deflecting electrodes of tube 2U are connected to circuitsI5, I6, respectively, to provide a deflecting potential which will serveto rotate the cathode ray beam in synchronism with the electronicrotation of the loop. As shown in this figure the output energy from theantenna is coupled over a vacuum tube 30 to a receiving detectorarrangement 40 to a coupling arrangement 4i. Arrangement 4l may, forinstance, be a re-modulating system in which the signals arere-modulated onto a fixed intermediate frequency so that the directionfinder is universally useful with all types of signals over a widefrequency range. The output of lll is coupled through a detector tube i2to spaced points on a resistance element d3, which serves to provide theoperating potentials for the electrodes of cathode ray tube 2U.

Cathode ray tube 2t is provided with an electron emitting cathode 2l, acontrol grid V22, a focusing element 23, and an accelerating electrode24. It will be noted that as connected, the output of tube d2 will varythe poten-tial on accelerating electrode Zit. This variation in voltagewill velocity modulate the electron beam and will thus cause a radialdisplacement of the beam of the cathode ray tube. It can, therefore, bereadily geen that the rotated electron beam will be deflected radiallyeither inwardly or outwardly under control or the envelope potentials.Thus, a pattern will be produced on the screen of cathode ray tube Z9indicating the direction of reception of signals. If desired a sensingantenna 2t may'beprovided 'to avoid the ambiguity of indication.

It will be seen that if no further circuits are provided, the cathoderay beam will continuously trace a circle on the face of cathode raytube 2G, even if the receiving circuit is arranged so that only peakpotential is applied to the electrode 2li'. It it is'desired to avoidthis continuous trace, a system may be arranged to maintain grid 22Ybiased substantially to cut-off, except at periods during which anindicating portion of the Vsignal envelope is being received. In. Fig. lthis is provided by means of a rectifier tube l5 coupled to the outputof di, which rectifier supplies energy over Vampliiier '56 to aresistance unit il in the normal vbiasing circuit of grid 22. Tube 156is provided with a self-biasing resistance condenser circuit li. Aswitch Si is provided so that the energy from rectifier i5 may beapplied either to increase or decrease the negative potential on grid'22. By this arrangement the cathode ray tube may be arranged to beeither bright during the signal reception, and dark the remainder of thetime, or dark during signal reception and bright the remaining portionof the time. The self-biasing circuit '123 serves to maintain the properbias on amplifier tube (it, to maintain the proper relation betweenvoltages from rectifier 5 regardless of the 'position of switch 159.

In Fig. 2 is provided an alternative black-out arrangement vfor the beamof cathode ray tube 2d, the circuit shown being capable of substitutionfor that part of the circuit oi Fig. l, shown between lines AA and BB.In this arrangement the energy from rectifier t is applied over apotentiometer resistance 6E? to amplier llt, so that the degree ofbrightness of the beam may be readily controlled. Also, thepotentiometer 6l is provided to adjust the amount of rectifier voltagesupplied across potentiometer til. This circuit provides for readyadjustment of the potential applied to the grid 22 of tube 2t.

An alternative and preferred arrangement for the rectiiier unit is shownin Fig. 3. In Vthis arrangement the entire part ofthe circuit of Fig. 1,cut-off at lines AA, BB and CC, should be replaced by that shown in Fig.3. In place of tube 4Z is provided a tube of the 6Q7 type which replacesboth amplifier 42 and rectifier 45. Tube 46 is replaced by a tetrodetube 63.

In place of the entire cathode ray assembly of Fig. l, may besubstituted the alternative arrangement of Fig. ll. In this arrangementthe cathode ray tube 2t is similarly provided with an acceleratingelectrode 25, concentrating electrode 23, grid 22 and cathode 2l. Theoutput of receiver 4t, however, is connected to the grid 22 of thecathode ray tube instead of to the accelerating electrode. Theaccelerating electrode is controlled by a relaxation oscillationgenerator BE. VThe period of relaxation oscillation generator 6G is madeto be long relative to the rotation frequency of the cathode ray beamand the effective rotation of the antenna system. Accordingly, a spiralpattern such as shown in Fig. 5 will normally be traced. However, grid22 of tube 2D is normally biased so that only at the indicating peak ofthe signal will an indication be Visible on the screen of cathode ray2U. Accordingly, when the direction signal is applied to grid 22, aseries of marks will appear on the screen producing a radial indication,as shown in Fig. 6. It can be readily seen that this type of indicationdepends upon the rotation of the electron beam and a simultaneous radialand emission control of the cathode ray beam.

Relaxation oscillator 'Ei' may be arbitrarily controlled in frequency solong as the period of its oscillation is made equal to a plurality ofrotations of the cathode ray beam. However, if desired, the generatormay be controlled directly from receiver B or from one oi the circuitsVI5 or l5, so as to produce oscillations which are a controlledsub-multiple of the rotation frequency of the cathode ray beam.

It is clear that many of the features disclosed above may be modiedwithout departing from the scope of my invention. Furthermore, althoughthere is a particular cooperation between the various elementscomprising the complete direction finder, some of these elements may beuseful in other circuits apart from the specic combinations recited. Forexample, the electronic rotation may be applied to circuits having othertypes or" radial deflection. vThis is not preferred, however, since Yinsuch a case it is necessary to provide an additional electronicdistributor or mechanical distributor for rotating the cathode ray beamin order that effective radial production of signals may be achieved.

It is also clear that the circuit arrangement of Fig. 5 may be utilizedindependently of the electronic rotation of the beam as can theindicator arrangement of Fig. l. However, if other forms of rotation areused the advantageous cooperation of the deflection indicator of thistype will be considerably lessened.

What is claimed is:

l. A direction finder comprising an aerial systeni means for producingan effective rotation of said aerial system to produce an indicatingvoltage dependent upon the effective angular position or" said aerialsystem with respect to a source of radiation, a cathode ray tubeindicator having an electrode system for producing a cathode ray beam,means for producing a rotation of said cathode ray beam in timedrelation with effective rotation Yof said aerial system, meanscomprising a saw-tooth oscillation generator having a .period equal to apredetermined number of rotations of said beam for causing a velocitymodulation of said beam to produce a, lateral deviation of said beam,and means comprising an electrode controlled by said indicating voltagefor controlling the intensity of said beam for applying said indieatingvoltage to said cathode ray tube to obtain a direction indication.

2. A direction iinder comprising an aerial system means for producingan'eiective rotation of said aerial system to produce an indicatingvoltage dependent upon the eiective angular position of said aerialsystem with respect to a source Aof radiation, a cathode ray tubeindicator having an electrode system for producing a cathode ray beam,means for producing a rotation of said cathode ray beam in timedrelation with eiective rotation of said aerial system, means comprisinga saw-tooth oscillation generator having a period equal to apredetermined number of rotations of said beam, for causing a velocitymodulation of said beam to produce a lateral deviation of said beam, andmeans for applying said indicating voltage to said cathode ray tube toobtain a direction indication. Y

3. A cathode ray tube indicator for use with an effectively rotatableaerial system having an elec-` trode system for producing a cathode raybeam, means for producing a rotation of said cathode ray beam in timedrelation With' effective rotation of said aerial system, meanscomprising a sawtooth oscillation generator having a period equal to apredetermined number of rotations of said beam for causing a velocitymodulation of said beam to produce a lateral deviation of said beam, asource of indicating voltage, and means for applying indicating voltagefrom said source to said cathode ray tube to produce an indication.

HENRI G. BUSIGNIES.

